First aid

You are a spectator at a football match. You are just returning to the stands and you hear someone shouting for help. You run to the scene and learn that one of the spectators fell out of his seat about a minute ago, slouched unnaturally, groaned, and then started twitching.

You don't wait for anything and start first aid. You promptly remove objects that may cause injury, support the head and loosen the clothing around the neck of the patient. What are your next steps?